1. Technical Field
The present invention relates to an apparatus for diagnosing a temperature detection unit, mounted in a vehicle provided with a power conversion circuit including a switching element, a control unit configured to operate the switching element to control a torque of a main rotating machine electrically connected to the power conversion circuit to a demanded torque, the temperature detection unit being configured to detect a temperature of the switching element.
2. Related Art
An apparatus for diagnosing a temperature detection unit, as disclosed in Japanese Patent Application Laid-Open Publication No. 2012-170211, is mounted in a vehicle provided with a power conversion circuit including a switching element, a control unit configured to operate the switching element to control a torque of a main rotating machine electrically connected to the power conversion circuit to a demanded torque, the temperature detection unit being configured to detect a temperature of the switching element. The apparatus estimates, on the basis of a current flowing through the switching element, a difference between a temperature of the switching element and a temperature reference value as a temperature change estimate, and calculates a difference between a detection value from the temperature detection unit and the temperature reference value as a temperature change measurement. The apparatus determines the presence of an abnormality in the temperature detection unit on the basis of a difference between the temperature change estimate and the temperature change measurement.
With the disclosed apparatus, however, a current may be supplied to the switching element for diagnosing the temperature detection unit regardless of a vehicle user's demand. Power is thereby supplied to the rotating machine as a prime mover from the power conversion circuit, which causes the rotating machine to output a torque. This may reduce drivability, thereby causing discomfort for the vehicle user or the like.
In consideration of the foregoing, it would therefore be desirable to have an apparatus for diagnosing the temperature detection unit without reducing drivability.